Add docs to the new build args

docs.md

@@ -109,7 +109,7 @@ If it's not a tag event, and no default branch, automated tags are skipped.
 | `default_tag`             | `latest`          | overrides the default tag name used when generating with `auto_tag` enabled
 | `label`/`labels`          | *none*            | sets labels to use for the image in format `<name>=<value>`
 | `default_labels`/`auto_labels` | `true`       | sets docker image labels based on git information
-| `build_args`              | *none*            | sets custom build arguments for the build
+| `build_args`              | *none*            | sets custom build arguments for the build. Key-Value pairs
 | `build_args_from_env`     | *none*            | forwards environment variables as custom arguments to the build
 | `quiet`                   | `false`           | enables suppression of the build output
 | `target`                  | *none*            | sets the build target to use
@@ -124,6 +124,26 @@ If it's not a tag event, and no default branch, automated tags are skipped.
 | `logins`                  | *none*            | option to log into multiple registries
 | `env_file`                | *none*            | load env vars from specified file
 
+## Build-Args example
+
+```yaml
+settings:
+  repo: a6543/tmp,codeberg.org/6543/tmp
+  tag: demo
+  build_args:
+    value1: hallo
+    value2: welt
+  logins:
+    - registry: https://index.docker.io/v1/
+      username: a6543
+      password:
+        from_secret: docker_token
+    - registry: https://codeberg.org
+      username: "6543"
+      password:
+        from_secret: cb_token
+```
+
 ## Multi registry push example
 
 Only supported with `woodpecker >= 1.0.0` (next-da997fa3).